The surface tension of which of the following liquids is the maximum ?

Options

A. `C_(2)H_(5)OH`
B. `CH_(3)OH`
C. `H_(2)O`
D. `C_(6)H_(6)`

Explanation

To determine which liquid has the maximum surface tension among the given options (ethanol, methanol, water, and benzene), we can follow these steps:

### Step-by-Step Solution:

1. **Understand Surface Tension**:
- Surface tension is a property of liquids that arises from the cohesive forces between liquid molecules. It is influenced by the type and strength of intermolecular forces present in the liquid.

2. **Identify the Intermolecular Forces**:
- The primary intermolecular force contributing to surface tension in liquids is hydrogen bonding. The more hydrogen bonds a liquid can form, the higher its surface tension will be.

3. **Analyze Each Liquid**:
- **Ethanol (C2H5OH)**: Ethanol can form hydrogen bonds due to the presence of an -OH (hydroxyl) group, but it has fewer hydrogen bonding sites compared to water.
- **Methanol (CH3OH)**: Methanol also has an -OH group and can form hydrogen bonds, but like ethanol, it has fewer bonding sites than water.
- **Water (H2O)**: Water has a unique structure that allows it to form up to four hydrogen bonds per molecule (two from the hydrogen atoms and two from the lone pairs on the oxygen atom). This extensive hydrogen bonding network gives water a very high surface tension.
- **Benzene (C6H6)**: Benzene is a non-polar molecule and does not form hydrogen bonds. Its surface tension is lower compared to the polar molecules mentioned above.

4. **Compare the Surface Tension Values**:
- Based on the analysis, water has the highest capacity for hydrogen bonding, which translates to the highest surface tension among the given options.

5. **Conclusion**:
- Therefore, the liquid with the maximum surface tension is **water (H2O)**.

### Final Answer:
The liquid with the maximum surface tension is **water (H2O)**.